Casseroles, which typically consist of a combination of vegetables, meat, pasta and/or rice, are cooked and served in a single large, deep dish. Casseroles are often topped with cheese as the primary surface ingredient. Due to the depth of a casserole, it can be difficult to cook the center of the casserole thoroughly, without excessively browning or burning the surface ingredients. Thus, casseroles are typically cooked for longer times and at lower temperatures as compared to the individual ingredients cooked alone.
Casseroles are currently prepared in an oven to achieve some browning of the casserole. During the browning process, also known as the Maillard reaction, reducing sugars and amino acids react at temperatures usually in the range of about 300-500° F. and break down relatively large, dull tasting molecules into relatively small, volatile molecules having a pleasing taste and odor. Thus, the browning process gives the casserole a desired flavor in addition to changing the color of the surface of the casserole. Browning occurs only at the surface because the moisture in the casserole prevents the interior from reaching temperatures required for the Maillard reactions to take place. The browning Maillard reaction, however, cannot occur at the surface of the casserole in an overly humid cooking cavity. As a result, casseroles are typically cooked without the addition of moisture. However, the longer cook times required for casseroles expose the surface ingredients of the casserole to radiant heat that can dry out, over-brown and even burn the surface ingredients. To prevent this, casseroles are covered with foil for part of the baking time. This is inconvenient and users often forget to remove the foil and the surface ingredients are not browned as desired.
The addition of water onto the surface ingredients can slow the surface browning. However, current methods of applying water to the surface ingredients by direct spray or steam are not convenient for the user nor do they produce predictable results. If too much water is used, the surface ingredients may appear uncooked and be soggy. If too little is used, the surface ingredients may burn.